This invention relates to a fluid circulating apparatus for use with a drill that creates holes in concrete, rock, or other materials.
The drill includes a bit that cuts and creates holes in an object to be drilled made of concrete, rock, or other materials, and a bit driving means for imparting a rotary motion to the bit, and allows the bit to rotate on an axis thereof, and to travel along the axis with the bit driving means. Conventionally, such a drilling operation has normally been carried out with water as a coolant (hereinafter referred to as cooling water) supplied via a fluid inlet provided in the bit.
The cooling water not only quenches heat generated by friction between a cutting edge of the bit rotating at high speed and the object to be drilled, but also serves to lubricate the rotating bit and to lessen abrasion of the cutting edge of the bit. Further, cooling water serves to flush out a large number of chippings produced through cutting and drilling operations by the drill.
The cooling water having the above features is normally supplied from a waterworks in a working place, and a considerably large amount of the cooling water is required for completion of the drilling operation.
On the other hand, not every working place has a waterworks equipped sufficiently. Since cooling water is required for carrying out a drilling operation in such a working place as well, operators should arrange in advance water to be used as cooling water in a container such as a bucket or pail. In most instances, the amount of the water prepared for that purpose is inevitably restricted to a minimum due to working place conditions or for reasons of transport.
The drilling operation performed with a limited amount of cooling water would require drilling as many holes as possible using the limited amount of cooling water, and thus would result in an extremely restricted amount of cooling water available for each hole. In many instances, the operation is carried out with a minimum operable amount of cooling water.
However, when the operation is carried out with a minimum operable amount of cooling water, the cutting edge of the bit is likely to become dull. Accordingly, operation time would become longer, and thereby subsequent operations would be affected.
Moreover, since the cooling water is not reused, the minimized amount of water prepared in advance becomes short in most cases. If the cooling water becomes short, an operator need go to a waterworks far from his/her working place to make up water. An interruption thus made during making up the cooling water would result in reduced working efficiency.
If the working place is located high in a high-rise building or the like, the water makeup operation produces sheer physical exhaustion of the operator, to say nothing of extra time required for making up the cooling water. Besides, the operation of carrying heavy water to be made up entails a danger.
Further, the cooling water also serves to flush out chippings produced through the drilling operation, and the cooling water discharged turns into a suspension containing the chippings. Consequently, the drilling operation usually accompanies an operation of collecting the suspension into another container to maintain cleanliness of the working place, and such a collecting operation is very burdensome.
Therefore, it is an exemplified object of the present invention to provide a fluid circulating apparatus for a drill in which a burden on an operator is alleviated by sparing the operator the inconveniences of making up cooling water, even if only a small amount of cooling water is available, and a suspension is collected and reused.
In order to achieve the above object, there is provided a fluid circulating apparatus for a drill according to the present invention. The drill includes a bit, a bit driving means that drives the bit to rotate, and a fluid inlet used to supply a coolant to the bit; the drill cuts and drills an object to be drilled by rotating the bit while supplying the coolant to the bit. The above fluid circulating apparatus for a drill comprises a suspension collecting means that collects a suspension derived from the coolant mixed with chippings through cutting and drilling operations, a suspension filtering means that filters off the chippings included in the suspension, thereby making the suspension back into the coolant to be stored in a reservoir, and a coolant supplying means that supplies the coolant obtained by the suspension filtering means and stored in the reservoir to the bit. The above suspension collecting means includes a vacuum pump used to collect the suspension through a discharge channel from a water receiving pad so provided as to surround a point to be drilled, while the vacuum pump changes a pressure in the reservoir to subatmospheric pressure.
The coolant is a fluid supplied to the bit for cooling the bit or other purposes, and includes no chippings, or only a trace quantity of chippings.
The suspension is a coolant in which chippings produced by cutting and drilling operations are mixed; thus, the suspension as-is is not suitable for a coolant to be supplied to the bit.
The suspension filtering means passes the suspension to filter off the chippings in the suspension, and thereafter stores the resultant fluid for future use as a coolant in the reservoir.
The present invention has several means for supplying a coolant, collecting a suspension containing chippings, filtering the suspension, and then supplying the filtered fluid as a coolant again. Accordingly, the coolant may be circulated and reused, so that the drilling operation may be performed with a small amount of the coolant.
The vacuum pump used herein to collect the suspension through the discharge channel from the water-receiving pad may contribute to stable collection of the suspension.
Preferably, the fluid circulating apparatus for a drill may further comprise a convection prevention cover between the vacuum pump and a water surface in the reservoir. The convection prevention cover may be disposed in a position where the convection prevention cover may be kept in contact with the water surface in the reservoir.
The convection prevention cover serves to restrict generation of turbidity and convection in the collected suspension. The convection prevention cover also serves as a cover to prevent the suspension from being sucked by the vacuum pump.
The above coolant supplying means may preferably include a pump provided in the reservoir to supply the coolant stored in the reservoir to the bit. The pump may preferably be provided in a floating state on a fluid surface of the coolant to feed a top layer of the coolant to the bit.
The coolant supplying means may preferably include a grain mixing means that mixes the filtered coolant with grains for grinding a cutting edge of the bit.
The grains mixed in the coolant may sharpen the cutting edge of the bit that is likely to become dull.
The suspension collecting means may preferably include a suspension dispersion jig provided at an end of the discharge channel through which the suspension is collected. The suspension dispersion jig includes a cylindrical body part shaped like a cylinder having a bottom end closed, and a branched part that branches out in a predetermined vertical position relative to the closed bottom end of the cylindrical body part. The branched part is shaped like a cylinder having a bottom end closed, and an opening through which the suspension is flown out is formed in the branched part. This structure serves to disperse the suspension uniformly in the filter.
Other objects and further features of the present invention will become readily apparent from the following description of preferred embodiments with reference to accompanying drawings.